If a hitter is good enough and/or has just the right combination of skills to play in the majors for a very long time, and is fortunate enough to have the high-leverage stars align perfectly in his favor often enough, and is opportunistic enough to cash in on such chances whenever they fall into his lap, he might have a game like David Murphy had last night once every 2-3 full seasons. Since baseball integrated in 1947, the average has been more along the lines of once every 4-5 full seasons, and I can't even begin to number all of the major league hitters who came and went through the league without ever pulling it off even once.
What I'm speaking of boils down to win probability added (WPA), or, as Tom Tango has described it on more than one occasion, "the statistic that tells a story." Because last night, David Murphy drew two walks, cranked a go-ahead home run, and laced a walk-off single against the greatest relief pitcher in baseball history en route to amassing a single-game WPA of .576 * -- something that I would likely not spend quite so much time focusing on if not for the fact that Murphy, of all people, singlehandedly took over a game against the reigning World Series-champion Yankees. The rarity of that number rightly reflects his dominance.
[Dating back to the 1950 season (which is as far back as WPA statistics have been tracked to date), there have been 1,972,274 player games where a batter has logged at least three plate appearances in a single game. Of that number, only 3,320 -- or one out of every 594 games -- have featured a single-game WPA greater than or equal to .570.]
Year in and year out, David Murphy has epitomized the league-average player. He can hit for some average, but not to an excessive degree. He has some pop, and perhaps even a surprising amount of it for a slender-framed outfielder whose entire game -- from his swing motion to his gait to his manner of throwing -- I've always internally thought of as "mechanical," but never has and never will be a huge power threat. He's solid enough defensively when tucked away in a corner outfield spot, but isn't anything special in that regard and isn't a viable center field option. He's not going to be Paul O'Neill or Rusty Greer (comps which always struck me as not only excessively optimistic, but also unfair), and optimally you look at him more as a very good fourth outfielder on a first-division ballclub than a starting-level outfielder.
That isn't presently the case, because Julio Borbon went ice-cold and Murphy caught fire and is now, for all intents and purposes, the Rangers' starting left fielder; the only certainty about this arrangement is that it's relatively short-lived, because eventually Josh Hamilton will land in left field again out of deference to Hamilton's durability -- or seeming lack thereof -- and Murphy will again find himself relegated to a lesser role. But the mere fact that he does hint at being more than a fourth outfielder from time to time is a very nice thing, because World Series-caliber teams like Texas feature capable role players like Murphy. And sometimes, like last night, they end up making a considerable difference.